Deduction and Induction

Vocabulary flashcards defining core concepts of deduction, induction, argument types, validity, soundness, strength, and cogency.

Factual Claim

A claim evaluated by determining the truth of the premises to see if the premises are indeed factual.

Inferential Claim

A claim evaluated by determining the relation between the premises and the conclusion to see if the conclusion follows from the premises.

Deductive Argument

An argument incorporating the claim that it is impossible for the argument to be false, given that the premises are true, involving necessary reasoning.

Inductive Argument

An argument incorporating the claim that it is improbable for the argument to be false, given that the premises are true, involving probabilistic reasoning.

Argument Based on Mathematics

A deductive argument in which the conclusion depends on some purely arithmetic or geometric calculation.

Argument from Definition

A deductive argument in which the conclusion is claimed to depend merely on the definition of some word or phrase used in the premise or conclusion.

Categorical Syllogism

A syllogism in which each statement begins with one of the words "all", "no" or "some".

Hypothetical Syllogism

A syllogism having a conditional statement for one or both of its premises.

Disjunctive Syllogism

A syllogism having a disjunctive statement (i.e. an "either…or…" statement) for one of its premises.

Prediction

An inductive argument that proceeds from our knowledge of the past to a claim about the future.

Argument from Analogy

An inductive argument that depends on the existence of an analogy, or similarity between two things or states of affairs.

Generalisation

An inductive argument that proceeds from the knowledge of a selected sample to some claim about the whole group.

Argument from Authority

An inductive argument that concludes something is true because a presumed expert or witness has said that it is.

Causal Inference

An inductive argument that proceeds from knowledge of a cause to a claim about an effect, or, conversely, from knowledge of an effect to a claim about a cause.

Valid Deductive Argument

A deductive argument in which it is impossible for the conclusion to be false, given that the premises are true.

Invalid Deductive Argument

A deductive argument in which it is possible for the conclusion to be false, given that the premises are true.

Sound Argument

A deductive argument that is valid, and has all true premises.

Unsound Argument

A deductive argument that is invalid, or has one or more false premises, or both.

Strong Inductive Argument

An inductive argument in which it is improbable that the conclusion be false given that the premises are true.

Weak Inductive Argument

An inductive argument in which the conclusion does not follow probably from the premises, even though it is claimed to.

Cogent Argument

An inductive argument that is strong, and has all true premises.

Uncogent Argument

An inductive argument that is weak, or has one or more false premises, or both.